The present invention generally relates to delivery systems for delivering a beneficial agent to a patient. More specifically, the invention relates to means for attaching vials to connection sites.
Many drugs are mixed with a diluent before being delivered intravenously to a patient. The diluent may be, for example, a dextrose solution, a saline solution or even water. Many such drugs are supplied in powder form and packaged in glass vials or ampules. Other drugs, such as some used in chemotherapy, are packaged in glass vials or ampules in a liquid state.
Powdered drugs may be reconstituted in a well known manner, utilizing a syringe which is used to inject liquid into the vial for mixing, the syringe eventually withdrawing the mixed solution from the vial. When a drug must be diluted before delivery to a patient the drug is often injected into a container of diluent after it is reconstituted, where the container may be connected to an administration set for delivery to a patient. More specifically, the diluent is often packaged in glass bottles, or flexible plastic containers such as are sold under the names MINI-BAG.TM. and VIAFLEX.RTM. by Baxter Healthcare Corporation of Deerfield, Ill. These containers have administration ports for connection to an administration set which delivers the container contents from the container to the patient. The drug is typically added to the container through an injection site on the container.
Drugs may be packaged separately from the diluent for various reasons. One of the most important reasons is that many drugs do not retain their chemical and physical stability when mixed with a diluent and thus cannot be stored for any substantial period of time. Also, drugs are often packaged separately from the diluent because many firms which manufacture drugs are not engaged in the business of providing medical fluids in containers for intravenous delivery, and vice versa.
Therefore, a doctor, nurse, pharmacist or other medical personnel must mix the drug and diluent. This presents a number of problems. The reconstitution procedure is time consuming and requires an aseptic technique. The operator must provide the proper diluent and a syringe before beginning. Often the powdered drug is "caked" at the bottom of the vial. Thus, when liquid is injected into the vial from a syringe the surface area of contact between the liquid and the powdered drug may be quite small initially, thus making the mixing procedure even more time consuming.
Because of the limited vial volume, the increasing drug concentration in the diluent makes it harder to finish the reconstitution process. The operator may attempt to solve this by repeatedly injecting solution into the vial, mixing and withdrawing the solution. This technique requires additional injections and movement of the syringe which increase the likelihood of contamination. Also, it is sometimes difficult to get all of the drug and/or liquid out of the vial, thus increasing the time required to perform the reconstitution procedure.
The reconstitution procedure should be performed under preferably sterile conditions. In addition to such a requirement making the operator justifiably more cautious and consuming more time, sterile conditions are often hard to maintain. In some instances, a laminar flow hood may be required under which the reconstitution procedure is performed.
Some drugs, such as some chemotherapy drugs, are toxic. Exposure of the operator to the drugs during reconstitution may be dangerous, especially if the operator works with such drugs on a daily basis and is repeatedly exposed to them.
A further problem is that the reconstitution procedure provides a source of confusion as to which container contains which drug. The diluent container should be marked with the drug with which it has been injected and the name of the patient to whom it should be delivered.
After a drug is reconstituted and withdrawn into a syringe barrel, the drug may in some instances be injected immediately into the intravenous system of a patient. More typically, however, the reconstituted drug is injected from the syringe into a larger container of solution as discussed above, for connection to an intravenous administration set. This is because often the drug reconstituted in the syringe is still at a concentration so high as to cause local toxicity in the veins of a patient near the injection site where the needle pierces the skin. This may create severe vein irritation which may be medically harmful.
Additionally, even though the proper dose of medication is in the syringe, immediate injection into the patient's blood stream may create a condition of systemic toxicity wherein the level of drug concentration in the patient's entire blood stream is dangerously high. Yet another reason for not making the injection from the syringe directly into the patient is that it creates an additional injection site into the patient, which may be painful for the patient and provides another opportunity for infection.
For these reasons, the reconstituted drug is more typically injected into a diluent container.
A patient may typically be administered a dextrose or saline solution from a large volume parenteral container, for example, such as a one liter container, delivered through an administration set such as a CONTINUFLO.RTM. administration set sold by Baxter Healthcare Corporation. If the reconstituted drug were injected into the large volume parenteral container, delivery of the drug would usually be made over too long a time period. Often, these large volume fluids are delivered at very slow flow rates.
More typically, the reconstituted drug is injected into a small volume parenteral container, such as a fifty milliliter container sold by Baxter Healthcare Corporation. This MINIBAG.TM. container is hung at a higher elevation than the large volume parenteral container and is connected by a secondary administration set to an injection site on the primary administration set. Because it is maintained at a higher elevation, the reconstituted drug in the small volume container is delivered, after which fluid from the large volume container begins to flow once more. By utilizing a small volume container connected to an administration set for delivery of the drug or other beneficial agent instead of a direct syringe injection, the drug is delivered over a preferred time period that tends to minimize negative side effects.
U.S. Pat. No. 5,049,129 discloses a passive drug reconstitution and delivery system with liquid flowing through an administration set. A receptacle mounted in the administration set is adapted for receiving a cartridge containing a beneficial agent. Also disclosed are adapter means for connecting the cartridge or a vial and the receptacle and an air flask within the administration set. One adapter includes an enlarged vial end constructed to snap fit about the mouth of a standard vial and a hollow shell configured to engage the receptacle. A sliding plate is positioned within the hollow shell and includes two separate cannulas acting as flow path means, for creating fluid paths through the vial to ensure proper mixing of the beneficial agent within the vial.
U.S. Pat. Nos. 4,804,366 and 4,850,978 disclose drug delivery systems with other adapters designed for use in the cartridges of those systems in which the cannula structures are rigidly mounted. However, in the disclosed adapters, the outside diameter of the vials useable therein is limited as a function of the interior diameter of the adapter.